A study on subjective response to heavy-weight impact sound through representative spectrum analysis: A case study in South Korea

Abstract

This study aims to suggest representative spectra of heavy-weight impact sounds and subject responses. In 2004, the Korean government implemented mandatory criteria that require a minimum concrete slab thickness of 210 mm for box-frame reinforced concrete apartment houses. Spectra representative of 140 households was derived through unsupervised cluster analysis of heavy-weight impact sounds made by rubber balls and tires. As a result, the frequency spectra and single-number quantities measured from apartments constructed before the standard was applied (110–180 mm) and those of apartments built after the introduction of the standard (210 mm) were found to be different. Based on the impact sounds created by a rubber ball and a tire, a sound pressure level in the 63–125 Hz band (Spectrum 1) was dominant for apartment houses with a floor slab of 210 mm. In apartment houses with a slab thickness of 110–180 mm, a sound pressure level in the 125–500 Hz band was relatively high (Spectrum 2 and 3). A total of 108 subjects with normal hearing were asked to express their level of annoyance relative to the sounds created by the rubber ball and tire. Spectrum 1 for the rubber ball showed a lower percentage of highly annoyed (%HA) than Spectrum 2 and 3 less than 60 dB (LiA,Fmax). In Spectrum 1, the tire elicited a higher %HA compared with Spectrum 2 and 3 above 50 dB (LiA,Fmax). Five categories of heavy-weight impact sounds with different spectra are suggested based on the annoyance responses of subjects.